Industrial and power generation gas turbines have control systems (“controllers”) that monitor and control their operation. These controllers govern the combustion system of the gas turbine and other operational aspects of the gas turbine. Typically, the controller executes scheduling algorithms that adjust the fuel flow, angle of the inlet guide vanes (IGV) and other control inputs to ensure safe and efficient operation of the gas turbine.
Gas turbine controllers typically receive input values of measured operating parameters and desired operating settings (e.g., power output, exhaust energy and the like) that, in conjunction with scheduling algorithms, determine settings for control parameters (e.g., fuel flow, combustor fuel splits, IGV angle, inlet bleed heat flow and the like) to achieve desired operation of the gas turbine. It is generally presumed that the values prescribed by the scheduling algorithms for the control parameters will cause the gas turbine to operate at a desired state, such as at a desired power output level and within defined emission limits. Thus, the scheduling algorithms incorporate assumptions regarding the gas turbine, such as that it is operating at a certain efficiency, with a certain flow capacity and at other assumed conditions. However, as the gas turbine operates for an extended period, component efficiencies tend to degrade and flow capacities and other operating conditions vary from the assumed conditions. Because of this deterioration, the scheduling algorithms become increasingly out of tune and cause the gas turbine to operate at states that increasingly diverge from the desired operational state.
To correct for changes in efficiency, flow capacity and other operating conditions, a gas turbine must be periodically “tuned.” Typically, this entails an engineer or technician manually adjusting the gas turbine, which requires that the gas turbine be taken off-line to be instrumented for tuning. To prevent the downtime required for manual tuning, U.S. Pat. No. 7,742,904 (assigned to the General Electric Company) discloses a system and method that automatically adjusts the mathematical model for a gas turbine to account for changes (e.g., changes in component efficiencies and flow capacities) that occur during long term operation of the gas turbine. Specifically, the system and method utilizes differences in modeled and sensed operating parameters of the gas turbine to generate correction factors with a Kalman filter gain matrix, which may then be used to adjust the mathematical model of the gas turbine. While the system and method disclosed in U.S. Pat. No. 7,742,904 offer substantial advantages, it has been recognized that improvements may be made to such a system and method to further enhance the accuracy of the mathematical model. For instance, specific improvements to the methodology used to predict operating parameters of a gas turbine compressor may be implemented to fine tune the model and, thus, enhance simulation of the compressor.
Accordingly, a system and method for enhancing simulation of a gas turbine compressor would be welcomed in the technology.